The Inverted Palace

This is what I sent my players as a little backstory for the big dungeon at the center of our campaign:

The Inverted Palace 

On clear days, at dawn or dusk, you can see it on the northern horizon. A wondrous palace—or, rather, an apparition of a palace. It disappears during the day and night, but journey into the dark forests beyond Linrik and you will find it again—no longer moored to the ground, but hanging upturned in the sky. Look up, and through the tree branches a host of majestic spires bears down on you from above. But this, too, is an apparition. It is only seen by those close to where the real palace once stood. 

For these apparitions are of the Palace Eternal, the seat of power for the lost Zenon empire and home to Anaktos the Stargiver, her final ruler. Zenon was the greatest of human civilizations. Its domain so vast it was said to have reached the stars. The sorcerers of Zenon, among whom Anaktos was the greatest, glimpsed the true mosaic of magic and established many of the spells practiced by today's lesser magicians. 

One lifetime was not enough for so great an authority as Anaktos. He became an undying lich to upheld his cruel and uncompromising reign for an aeon. But over the slow centuries he grew dissatisfied with earthly limitations and sought, as many foolish and powerful men do, ascension to godhood. A ritual was devised; it's culmination the sacrifice of every mortal within his empire. Five hieroknights, on whose brows each burned a star, learned of Anaktos's scheme and turned their swords upon their master. With five sacred blades they divided his soul into five equal parts, each borne in a piece of his body: hand, eye, heart, brain, and rib bone. The emperor's remains were banished along with his palace into the depths of the earth. The Palace Eternal became the accursed Palace Inverted, imprisoning Anaktos forevermore. 

 

All that remains above ground is a gate of white marble hidden among the trees. Beyond lies a courtyard of an antique style, columns enrobed in delicate moss. At its center an elegant staircase twists into the beckoning darkness below.

Some legends of the Inverted Palace: 

1. The Static Tower holds every failed experiment too dangerous or dear to Anaktos to dispose of. Some have broken free and now roam the halls of the palace. Bereft of  purpose, they create their own.
2. The palace keeps a record of every dream had within its walls. The archive spiders store them in waxy pearls that dangle from their webs. Anaktos’s dreams are locked away behind a door hidden within the Weird.
3. All semblances of Anaktos have been destroyed. The statues beheaded, the murals defaced, the mosaics plucked of their tiles. Every coin of the Zenon empire has a wide gouge on the obverse side where once glowered a noble profile. No record of the Eternal Emperor's face remains. 
4. Orcs, gnolls, and other half-men are drawn to the palace, yet those who enter may never leave. They hear the thrumming heart of Anaktos wherever they go.  
5. The palace guardians have pledged themselves to eternal duty. They're interred in heavy death-mask helmets that fit over the head and shoulders, denying them the peace of true death. 
6. A secret gallery has six gates: one may only be passed by the dreaming, one by the mad, one by the lost, one by the unseen, one by those geased to do so, and one only by the dead. 
7. The two-headed dragon emblem of Zenon represents life and death, heavens and earth, energy and mass—all of which Anaktos sought to master. The emperor courted both Law and Chaos, though refused to show fealty to either. Their influence was still new to this world at the assumption of his lichdom. Neither power intervened to prevent in his demise. 
8. The armory holds the Sword of Immanence, a weapon which strikes at the fundamental concept of its target. It may be wielded against anything from gods and monsters to metaphysics, ideas, and phenomena. Its use is an affront to reality.
9. The palace garden spreads like a mold, subsuming the territory far beyond the limits of its original domain. It must be appeased by the inhabitants of the palace else it will devour them all. 
10. Food, corpses, young love—nothing spoils in the kitchen.